Development and validation of a simple and sensitive high performance liquid chromatographic method for the simultaneous determination of anastrozole, bicalutamide, tamoxifen, and their synthetic impurities

Fabio Pereira Gomes, Pedro Lopez Garcia

Index: Talanta 101 , 495-503, (2012)

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Abstract

A simple and sensitive analytical method for simultaneous determination of anastrozole, bicalutamide, and tamoxifen as well as their synthetic impurities, anastrozole pentamethyl, bicalutamide 3-fluoro-isomer, and tamoxifen e-isomer, was developed and validated by using high performance liquid chromatography (HPLC). The separation was achieved on a Symmetry® C-8 column (100×4.6mm i.d., 3.5μm) at room temperature (±24°C), with a mobile phase consisting of acetonitrile/water containing 0.18% N,N dimethyloctylamine and pH adjusted to 3.0 with orthophosphoric acid (46.5/53.5, v/v) at a flow rate of 1.0mLmin−1 within 20min. The detection was made at a wavelength of 270nm by using ultraviolet (UV) detector. No interference peaks from excipients and relative retention time indicated the specificity of the method. The calibration curve showed correlation coefficients (r) >0.99 calculated by linear regression and analysis of variance (ANOVA). The limit of detection (LOD) and limit of quantitation (LOQ), respectively, were 2.2 and 6.7μgmL−1 for anastrozole, 2.61 and 8.72μgmL−1 for bicalutamide, 2.0 and 6.7μgmL−1 for tamoxifen, 0.06 and 0.22μgmL−1 for anastrozole pentamethyl, 0.02 and 0.07μgmL−1 for bicalutamide 3-fluoro-isomer, and 0.002 and 0.007μgmL−1 for tamoxifen e-isomer. Intraday and interday relative standard deviations (RSDs) were <2.0% (drugs) and <10% (degradation products) as well as the comparison between two different analysts, which were calculated by f test.